Model approaches for evaluation of cell coupling in monolayers.

The electrical coupling of epithelial cells of the intestine of chick embryo cultured in monolayers was studied. This coupling can be evaluated by regarding the monolayer as a honeycomb structure of cells and the cells as equipotential spaces, as long as the cells are small (diameter <25μm). With help of this discrete model it was found that for the non-junctional membrane the membrane resistance isϱ m =250-2,000 Ω cm(2), and for the junctional membraneϱ m =5-50 Ω cm(2). In addition to this discrete model, a continuous model was also considered and good agreement between the two descriptions was found. With the aid of the continuous model, a value for the non-junctional membrane capacitance (C m ) was obtained: 5-50 μF/cm(2). The electrical values are not corrected for membrane folding, microvilli and the like. Tentative corrections based on electron microscopy suggest: 1,000 <ϱ m < 10,000 Ω cm(2), 10 <ϱ m < 100 Ω cm(2), 1